
<h1><span class="yiyi-st" id="yiyi-12">numpy.expm1</span></h1>
        <blockquote>
        <p>原文：<a href="https://docs.scipy.org/doc/numpy/reference/generated/numpy.expm1.html">https://docs.scipy.org/doc/numpy/reference/generated/numpy.expm1.html</a></p>
        <p>译者：<a href="https://github.com/wizardforcel">飞龙</a> <a href="http://usyiyi.cn/">UsyiyiCN</a></p>
        <p>校对：（虚位以待）</p>
        </blockquote>
    
<dl class="data">
<dt id="numpy.expm1"><span class="yiyi-st" id="yiyi-13"> <code class="descclassname">numpy.</code><code class="descname">expm1</code><span class="sig-paren">(</span><em>x</em><span class="optional">[</span>, <em>out</em><span class="optional">]</span><span class="sig-paren">)</span><em class="property"> = &lt;ufunc &apos;expm1&apos;&gt;</em></span></dt>
<dd><p><span class="yiyi-st" id="yiyi-14">对数组中的所有元素计算<code class="docutils literal"><span class="pre">exp（x）</span> <span class="pre"> - </span> <span class="pre">1</span> </code></span></p>
<table class="docutils field-list" frame="void" rules="none">
<col class="field-name">
<col class="field-body">
<tbody valign="top">
<tr class="field-odd field"><th class="field-name"><span class="yiyi-st" id="yiyi-15">参数：</span></th><td class="field-body"><p class="first"><span class="yiyi-st" id="yiyi-16"><strong>x</strong>：array_like</span></p>
<blockquote>
<div><p><span class="yiyi-st" id="yiyi-17">输入值。</span></p>
</div></blockquote>
</td>
</tr>
<tr class="field-even field"><th class="field-name"><span class="yiyi-st" id="yiyi-18">返回：</span></th><td class="field-body"><p class="first"><span class="yiyi-st" id="yiyi-19"><strong>out</strong>：ndarray</span></p>
<blockquote class="last">
<div><p><span class="yiyi-st" id="yiyi-20">单元指数减1：<code class="docutils literal"><span class="pre">out</span> <span class="pre">=</span> <span class="pre">exp（x）</span> <span class="pre"> - </span> <span class="pre">/ t5&gt;</span></code>。</span></p>
</div></blockquote>
</td>
</tr>
</tbody>
</table>
<div class="admonition seealso">
<p class="first admonition-title"><span class="yiyi-st" id="yiyi-21">也可以看看</span></p>
<dl class="last docutils">
<dt><span class="yiyi-st" id="yiyi-22"><a class="reference internal" href="numpy.log1p.html#numpy.log1p" title="numpy.log1p"><code class="xref py py-obj docutils literal"><span class="pre">log1p</span></code></a></span></dt>
<dd><span class="yiyi-st" id="yiyi-23"><code class="docutils literal"><span class="pre">log（1</span> <span class="pre">+</span> <span class="pre">x）</span></code></span></dd>
</dl>
</div>
<p class="rubric"><span class="yiyi-st" id="yiyi-24">笔记</span></p>
<p><span class="yiyi-st" id="yiyi-25">This function provides greater precision than <code class="docutils literal"><span class="pre">exp(x)</span> <span class="pre">-</span> <span class="pre">1</span></code> for small values of <code class="docutils literal"><span class="pre">x</span></code>.</span></p>
<p class="rubric"><span class="yiyi-st" id="yiyi-26">例子</span></p>
<p><span class="yiyi-st" id="yiyi-27"><code class="docutils literal"><span class="pre">exp（1e-10）</span> <span class="pre"> - </span> <span class="pre">1</span></code>的真值是<code class="docutils literal"><span class="pre">1.00000000005e-10</span></code></span><span class="yiyi-st" id="yiyi-28">这个例子显示了expm1在这种情况下的优越性。</span></p>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="gp">&gt;&gt;&gt; </span><span class="n">np</span><span class="o">.</span><span class="n">expm1</span><span class="p">(</span><span class="mi">1</span><span class="n">e</span><span class="o">-</span><span class="mi">10</span><span class="p">)</span>
<span class="go">1.00000000005e-10</span>
<span class="gp">&gt;&gt;&gt; </span><span class="n">np</span><span class="o">.</span><span class="n">exp</span><span class="p">(</span><span class="mi">1</span><span class="n">e</span><span class="o">-</span><span class="mi">10</span><span class="p">)</span> <span class="o">-</span> <span class="mi">1</span>
<span class="go">1.000000082740371e-10</span>
</pre></div>
</div>
</dd></dl>
